Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=true, openWorldHint=true), so the bar is lower, yet the description adds genuine operation context: allocate private storage, save the connection before displaying results or making follow-ups, verify with the saved credential, and never print the credential. It does not explain why the tool is flagged destructive or non-idempotent, leaving that gap to the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, purpose front-loaded, then a packed sequence of operational instructions with no filler. It is slightly dense ('Prepare private storage first; save ... before displaying ... then verify') but every clause earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema exists, so the description must carry return handling, and it does explain the returned connection's lifecycle and the credential-verification step. It stops short of describing the pending/approved/denied status shapes an agent will receive, which is the main remaining gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both parameters are already documented. The description reinforces the receipt's origin and the connection's handling but adds no syntax or format detail beyond what the schema already provides, so baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb+resource ('Check a pending join ... and collect your credential') and ties itself to artifacts created by siblings (receipt from room_join, connection from room_bootstrap/room_join), so an agent can tell it apart from room_join and room_bootstrap without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives clear context for use ('after creator approval', 'with its saved private receipt') and states the precondition (prepare private storage first). It does not explicitly exclude alternatives or tell the agent what to do when no receipt exists, so it falls short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.